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Baraja's New Lidar Uses Rainbow Physics to Help Self-Driving Cars See

By making tiny adjustments to the wavelength of the infrared pulses it fires, Baraja's lidar dictates the angle at which they exit a prism—and the direction they take into the world.

Baraja

In the land of the self-driving vehicle, the car with the best lidar sensor is king. So goes the logic of the booming self-driving car industry. To drive safely, an autonomous vehicle needs to see the world around it, and the best way to do that is with a system that fires millions of pulses of light every second, measuring how long they take to bounce off nearby objects and building a detailed 3-D map.

Lidar, however, is hard. It’s a young technology—the first application designed specifically for driving dates to 2005—and remains expensive and unproven when it comes to the automotive grade reliability the car industry requires. That’s why dozens of lidar makers have emerged in recent years, each claiming they’ve got the laser-flinging solution that offers the right balance of range, resolution, robustness—and cost.

The latest newcomer to light up the dance floor is Baraja, an Australian startup founded by two former telecom workers. The key to their system? Prisms. Prisms and fiber optic cables.

One of the key challenges engineers face when they’re designing a lidar is how to move the laser back and forth, up and down, which is what it needs to do to take in all its surroundings. Velodyne, the oldest and biggest player in the market, sticks as many as 128 lasers into its sensor and spins the whole thing around 64 times per second. Luminar, a growing startup, with a pair of oscillating, dime-sized mirrors. The argument against such setups is that moving parts add complexity, and that they’ll only handle the rigors of the road for so long before breaking down.

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Baraja proposes a novel, mechanically simpler way to direct its laser sight. If you were paying attention in science class, you know white light going into a prism comes out divided into the colors of the rainbow on the other side. The order of that rainbow is based on the wavelength of each color. Red (around 700 nanometers) sits above orange (around 600). Indigo (420 to 440 nanometers) goes above violet (around 400).

The Australian lidar company uses this phenomenon to its advantage by shooting its single laser through what CEO Federico Collarte calls a prism-like material. He wouldn't provide details, but explains it's a sort of lens that refracts infrared light the way prisms do visible light. By making tiny adjustments to the wavelength of the infrared pulses it fires (all of them around 1550 nanometers), it dictates the angle at which they exit the glass—and the direction they take into the world. If it wants to focus its attention on one bit of the scene, it simply keeps pumping out pulses of light at the appropriate wavelength.

Baraja’s co-founders, Collarte and CTO Cibby Pulikkaseril, borrowed the idea from the telecoms industry, where they both worked until a few years ago. There, a technique called wavelength division multiplexing allows one optical fiber to carry a bunch of signals, each on a different wavelength. Prisms are one tool for combining and separating those signals. Collarte and Pulikkaseril saw a growing need for reliable lidar in the nascent self-driving car industry, and realized the tech they were already working on could be stuck on the roof of a car. In July of 2015, they launched Baraja. Now, with the fourth iteration of their system, they’re ready to show the world what they’ve made.

“We didn’t invent this laser, we didn’t invent prisms,” says Collarte. “We’re just taking mature concepts from telecoms and moving them to a new market.” A lucrative market. An April report from Woodside Capital Partners predicts the lidar industry will be worth close to $10 billion by 2032, as cars with varying levels of automation approach ubiquity.

Baraja’s lidar carries a second design quirk that its creators think sets them apart. Because its sensor has a limited field of view, it needs to fire lasers from various points on the car to see all its surroundings. Competing systems do that by installing a bunch of lidars, each carrying its own laser (or lasers). Baraja uses one laser per car, sitting inside a box the size of a wireless router. From deep inside the car, it fires its pulses of light, which travel through fiber optic cables to the several prisms that sit inside blue plastic casing at various points on the exterior of the car.

Baraja's single laser sits inside a box the size of a wireless router. The pulses of light it generates travel through fiber optic cables to the several prisms that sit inside blue plastic casing at various points on the exterior of the car. This setup, CEO Federico Collarte says, improves reliability and keeps maintenance costs low.

Baraja

The key advantage to this cyclopean setup is cost. You’re only paying for one main laser unit, and if one of those exterior units gets banged up by hail, a fender bender, or a malevolent pedestrian, it’s cheap and easy to replace. “You don’t want to pay an eye and a kidney for maintenance,” Collarte says.

Baraja’s lidar can see objects that reflect just 10 percent of light—think a pedestrian wearing black on a poorly lit street—from an impressive 240 meters, Collarte says. A self-driving developer would use an open API to program the laser, and would be responsible for analyzing the data that the system gathers. The Sydney-based company (which also has offices in Silicon Valley and China) took its name from the Spanish word for a deck of cards, whose size they hope to match with their laser unit. (It’s also the word for shuffle, which Collarte says goes nicely with their constant variation of laser wavelengths.)

The novelty of the system, though, means potential customers will need to do their due diligence. The prism setup can only move the beams of light up or down; Baraja still relies on what Collarte calls a “mechanical aid” to move them left or right (he wouldn’t provide details). The need to run fiber optic cables through a car could be a pain point for automakers. And while Collarte promises a cost-competitive system, he has to fight off a pile of competitors for each customer.

Still, the lidar market is growing fast and remains wide open. No one company is likely to dominate, especially since different applications of self-driving tech will require different sorts of vision systems, says Shahin Farshchi, a partner at the venture capital firm Lux Capital who has invested in lidar-maker Aeva, as well as self-driving startup Zoox. “It’s hard to imagine a one-size-fits-all product or technology.”

Baraja may not have a perfect system, but when it comes to the gift of sight, it’s willing to bet that one laser—and a few prisms—is all you need.